I will chime in here with some of my own opinions. I have had my two crabs (Sonny and Cher) for 9 years now. Started with a 10 gallon, then 20 gallon (both with saran wrap lids), and now have a nice 55 gallon that has a plexiglass lid that was given to me. I am pretty casual about some things with my crabs. I don't keep track of what I feed them when, or what they are eating/ drinking/ getting ready to molt, or even what day they disappear under the substrate.
I don't have calipers or a sizing mat - I try to measure the shell openings using a clear plastic ruler. Which can be interesting when they are actually in the shell, LOL. I figure the substrate should be at least 3 times as deep as my biggest crab's height if I look at him from the side. When I am going to add something plastic to the tank, I clean it with a vinegar and water mix, then rinse it with my fresh water (I use Reverse Osmosis water, which is equivalent to dechlor fresh water). If something can be boiled (ie - shells), I boil in the RO water. I have soaked wood items in salt water then baked in the oven (can't remember the exact time or temp, I think I found it on this site somewhere).
When I mixed my substrate (I use the 5 parts play sand to 1 part EE mix), I used the RO water because I didn't know any different. The reason some people use salt water is to decrease the chance of bacteria growing. Same reason to treat things like wood and hemp rope or netting, to prevent mold growth. The surface mold on things like that isn't harmful to the crabs, but some people can be allergic or sensitive to it.
To answer your questions:
1 - Can be one or can be multiple bowls, there is no right or wrong. Sometimes I put leaf litter or calcium in a separate bowl because it lasts longer than the other foods, and I can leave it in longer. Food can be separated or can be mixed together. Raw or cooked. Cut up or whole.
2 - See my estimating method above, LOL. There is more info about sizing in one of the care sheets.
3 - TV etc won't bother them. I have never been really specific with my light and dark times. I do not use a light source at all. My crabs are in my sewing room upstairs, which has a window. They get the number of hours of daylight and night time as per the seasons, so it does vary (I live in central Canada). I sew in the evenings in winter, so they have the room light. I would not recommend over thinking it, LOL.

Hope some of that helps!

Is it okay if I ask a follow up question even though I didn't start the thread? I don't mean to hijack at all but it came up here so maybe all 3 of us could benefit from hearing what you have to say about what kind of water you should spray your tank with if you need to up your humidity? I thought I read that you should spray anything going in the tank with salt water (I do use all of the cleaning/ sanitizing methods you described for new items going in or would do it that way for cleaning) but my new friend on here Kydra mentioned shed noticed a mineral film, then while looking for the information that said its good to add as much salt in ways you can like spraying, cleaning, ect, I ran into two posts regarding spray bottle water- one said don't use salt because it can build up and become dangerous to the crabs which was alarming ( I don't spray often my humidity is pretty stable) I have the link for that above, and then this one viewtopic.php?f=127&t=120613

Is this a clean cut thing? Should I ditch the salt spray bottle? Salt water sounds good for no bacteria but why could it be dangerous? Sorry trying to go back into the archives and I've searched in the finder and didn't find much more than the two links. thank you for your time and help!

Joked about being a crazy cat lady..
Turns out it’s crazy crab AND cat lady
2 PPs Captain Lee (the stud of the sea) & New Adoptee "Kyle" to be renamed
In the process of adopting 4 more
3 cat babies
RIP Unamed PP😔
Fell deep into this hermit crab hole and I’m not coming back

I could be completely wrong (obviously I am brand new to this) but as I read it when you first moistened the substrate you use the salt water, then the fresh water to mist and keep humidity up thereafter so the salt doesn’t build up. At least that’s how I read it. Please let me know if I’m wrong.

I have a brief moment to chime in... I guess my thought was the recommendation of saltwater to spray for humidity. The salt and minerals will build up over time as the water evaporates, but the salt doesn't. I will take a look at your links when I have some more time!

I mixed my substrate with dechlor Instant Ocean to inhibit some mold/bacteria growth and my humidity is always 80 or over, but I do use freshwater to spray now and then for reasons noted above instead of saltwater.

I'll have to catch up on this thread tomorrow as I just scanned through. I am on a mini-vaca and was asking where the hermit crab dads are as I am one of them haha. I am also in my 30's. Lots of new hermit crab moms, but still... where are the dads lol.

I am glad to be here regardless and fine with all the moms lol. Will read more into everything tomorrow for any unanswered/debatable questions/concerns. We are all in this together anyway. Also, there's so much information and misinformation out there sometimes better to just hear from another crabber! Will check back in when I have more time to read through everything.

Kydra - there are a few crab dudes on this site! MotorCrab, AussieJJ for sure. Maybe FinalxFantasy and PurplePincher too? I think many of the members are 'kids' (okay, I know I am old - after you turn 40, everyone under 30 looks like a kid, LOL!!) but there are definitely a number of over 30 year olds too!

I am pretty sure I recall the more experienced crabbers saying to mist with dechlor fresh water, not salt, due to the build up. Personally, my humidity has been good in both my 20 and 55 gallon and I have not had to spray.

"If there are no dogs in Heaven, then when I die I want to go where they went." -Will Rogers

Kydra - there are a few crab dudes on this site! MotorCrab, AussieJJ for sure. Maybe FinalxFantasy and PurplePincher too? I think many of the members are 'kids' (okay, I know I am old - after you turn 40, everyone under 30 looks like a kid, LOL!!) but there are definitely a number of over 30 year olds too!

I am pretty sure I recall the more experienced crabbers saying to mist with dechlor fresh water, not salt, due to the build up. Personally, my humidity has been good in both my 20 and 55 gallon and I have not had to spray.

Good to know I'm not the only 'dude' crabber lol. I realized after creating my username that it would be assumed I'd be a female . The username is actually the names of my two crabs combined into one.

I know what you mean about getting older. Everyone looks like kids yet I still remember those days when I thought 30 was OLD haha. Time flies though! Enjoying my mini-vaca for now. Will check back in as I can...

Oh and I'm using a wyze cam to spy on the crabs while I'm away. A bit much? Maybe, but I might be a little crazy!

Good to know I'm not the only 'dude' crabber lol. I realized after creating my username that it would be assumed I'd be a female . The username is actually the names of my two crabs combined into one.

I know what you mean about getting older. Everyone looks like kids yet I still remember those days when I thought 30 was OLD haha. Time flies though! Enjoying my mini-vaca for now. Will check back in as I can...

Oh and I'm using a wyze cam to spy on the crabs while I'm away. A bit much? Maybe, but I might be a little crazy!

A bit much? Nah. I have 2 cameras in 1 tank to make sure I see everything.

True on more disposable income... also true sometimes spending too much of it . Two cameras in 1 tank? I have mine outside the tank until I upgrade (maybe in tank after my 3rd upgrade lol). It's working well while away though; I can see the crabs in the main tank come out at night and still have my iso "pet sand" tank visible (please hurry it up on the molt lol).

I am likely adopting another crab on my way back from my vaca. Have to respond and get some pictures to make sure it's def a small guy as he'd be going in the 10 gallon for now. The current conditions aren't ideal from what I was told (boardwalk crab).

Now I feel like I'm hijacking this thread a bit, but would y'all go from a 10 gallon to a 20 long or 29? My molter might be an E which means more substrate, but could have just been pale prior to molting so that will factor in, but assuming all PPs which would be more ideal? I'll check out the dimensions again, but was thinking 20 long.

Oh and congrats @curlysister on your 9 year anniversary and 9 years with your crabs!!!

I love all this info! I added a plastic platform to my tank and I’m wondering if this needs the same level of substrate or will the “first floor” suffice? As of now I just put a little on the platform so they wouldn’t be walking on plastic.
Also my crannies have been hanging in the same spot for a while now, I saw Batman come down to eat some mealworm last night but he went straight back to their spot after. Should I be worried or are they just getting used to the new digs? They seemed to be more active the first two days, granted I’m only at day 5 with them now?